The proposal is for the evaluation of hyperopic and astigmatic thermokeratoplasty using a newly available continuous wave (cw) laser as an alternative to pulsed lasers. The hypothesis to be tested is that continuous wave infrared laser radiation can produce controlled heat shrinkage of collagen fibers in the cornea for correction of refractive errors, with greater long term predictability than pulsed lasers such as the Ho:YAG. The new infrared laser will be tuned to wavelength allowing delivery of non-coagulating heat to stromal tissue, while minimizing heating of Bowman's and Descemet's layers and the corneal endothelium. A modulated delivery system will deliver power in a ring-shaped pattern to correct hyperopic refractive errors, or vary power delivery to selected areas of the corneal to correct astigmatism. Preliminary experiments in this laboratory indicate that myopic correction may also be achieved. Experiments in live animals will determine long-term beneficial and adverse effects. The long term objective of this research plan is the development of a compact commercial laser device providing a low risk alternative to radial keratotomy and photo refractive keratotomy by avoiding scarring or irregularity of the optical zone.